The United States on Friday congratulated Armenia and Azerbaijan on concluding negotiations on a historic peace treaty. The US described it as an opportunity for both nations to turn the page on a decades-old conflict,

Armenian and Azerbaijani officials said on Thursday that they had agreed the text of a peace agreement to end nearly four decades of conflict between the South Caucasus countries, a sudden breakthrough in a fitful and often bitter peace process.

But hurdles remain. Azerbaijan also said Armenia’s constitution must “eliminate the claims against the sovereignty and territorial integrity of Azerbaijan,” as a prerequisite to allow for the signing of the peace treaty.